Biomedical subjects

James E Lingeman

Publications and source records attributed to James E Lingeman.

At least 73 records · Page 4Linked to original sources

PubMed2002

Stone fragmentation during shock wave lithotripsy is improved by slowing the shock wave rate: studies with a new animal model.

PURPOSE: The current trend toward ungated shock wave lithotripsy means that more patients are being treated with shock waves delivered at a rapid rate (120 shock waves per minute or greater). However, no benefit of an increased shock wave rate has been shown and in vitro studies indicate that slowing the shock wave rate actually improves stone fragmentation. We tested the effect of the shock wave rate on stone comminution in a new animal model. MATERIALS AND METHODS: Gypsum model stones were inserted via upper pole percutaneous access into the lower pole calix of the kidneys of female pigs weighing approximately 100 pounds. Shock wave lithotripsy was performed (400 shock waves uninterrupted at 20 kV. and 30 or 120 shock waves per minute) 2 hours later using an unmodified HM3 lithotriptor (Dornier Medical Systems, Marietta, Georgia). After en bloc excision of the urinary tract stone fragments were collected and sieved through 2 mm. mesh. The particles were weighed and surface area was determined. RESULTS: Stones treated at 30 shock waves per minute broke more completely than stones treated at 120 shock waves per minute. The percent of fragments greater than 2 mm. was significantly higher for stones treated at the fast rate of 120 versus the slow rate of 30 shock waves per minute (mean +/- SEM 81% +/- 14% versus 45% +/- 12%, p <0.005). When stone fragmentation was expressed as the percent increase in fragment surface area, significantly greater fragmentation occurred at the slower than at the more rapid rate (327% +/- 63% versus 135% +/- 136%, p <0.02). CONCLUSIONS: Slowing the rate of shock wave administration during shock wave lithotripsy significantly improves the efficiency of stone fragmentation in vivo.

Animals↗

PubMed2002

Multilayered small intestinal submucosa is inferior to autologous bowel for laparoscopic bladder augmentation.

PURPOSE: Bladder augmentation is most commonly performed with ileum. However, porcine small intestinal submucosa has been reported as a substitute for bowel for incorporation into the urinary tract. We assessed the feasibility and long-term 12-month results of laparoscopic bladder augmentation with ileum or multilayered small intestinal submucosa (Cook Biotech, Spencer, Indiana) in a porcine model. MATERIALS AND METHODS: We performed laparoscopically assisted hemicystectomy and bladder augmentation in 24 female Yucatan mini-pigs using an ileal segment (12) or multilayered small intestinal submucosa (12). The followup protocol included anesthetic bladder capacity, renal ultrasonography and serum chemistry. At 3, 6 and 12 months, respectively, 4 animals per group were scheduled for sacrifice and pathological analysis. RESULTS: Despite longer anastomotic time in the multilayered small intestinal submucosa group (120 versus 91 minutes, p = 0.026) total operative time was similar in the 2 groups. In each group bladder capacity increased with time but by 12 months bladder capacity was significantly better in the bowel than in the small intestinal submucosa group (825 versus 431 cc, p = 0.016). At 3 months pathological evaluation revealed that the multilayered regenerated bladder patch had shrunken and by 6 months it was replaced by dense calcified scar tissue. Long-term 6 and 12-month bladder capacity in the small intestinal submucosa group was the result of the regeneration of native bladder with exclusion of the whole multilayered patch in the majority of cases. CONCLUSIONS: Laparoscopic bladder augmentation using multilayered small intestinal submucosa produced functional and pathological results inferior to those of bowel at 12-month followup in a porcine model.

Animals↗

PubMed2002

Major complications in 213 laparoscopic nephrectomy cases: the Indianapolis experience.

PURPOSE: We assessed the incidence of and analyzed factors that may help prevent major complications and open conversion during laparoscopic nephrectomy at our institutions. MATERIALS AND METHODS: We retrospectively analyzed all laparoscopic nephrectomies performed between August 1, 1999 and July 31, 2001. Data were stratified for nephrectomy type, intraoperative and postoperative complications. Conversion to open surgery was stratified for emergency versus elective procedures. RESULTS: Of the 292 laparoscopic procedures performed at our institutions in 2 years 213 (73%) involved laparoscopic nephrectomy, including 84 live donor nephrectomies, 61 radical nephrectomies, 55 simple nephrectomies and 13 nephroureterectomies. A total of 16 major complications (7.5%) occurred, including access related, intraoperative and postoperative complications in 3, 9 and 4 cases, respectively. The conversion rate was 6.1% (13 patients), the transfusion rate was 1.9% and the mortality rate was 0.5% (1 death). Only 1 complication was related to simple laparoscopic nephrectomy, although this group showed the highest rate of elective conversion (7 of 8 elective conversions). Laparoscopic live donor nephrectomy showed the highest rate for emergency conversion (3 of 5 emergency conversions). CONCLUSIONS: Our results reinforce the importance of thorough preoperative imaging, careful patient selection, surgeon experience and skill maintenance in laparoscopy as well as a low threshold for conversion to open surgery. This series provides additional evidence to support the evolution of laparoscopic nephrectomy into a standard of care.

Adult↗

PubMed2002

Kidney damage and renal functional changes are minimized by waveform control that suppresses cavitation in shock wave lithotripsy.

PURPOSE: In studies to understand better the role of cavitation in kidney trauma associated with shock wave lithotripsy we assessed structural and functional markers of kidney injury when animals were exposed to modified shock waves (pressure release reflector shock pulses) that suppress cavitation. Experiments were also performed in isolated red blood cells, an in vitro test system that is a sensitive indicator of cavitation mediated shock wave damage. MATERIALS AND METHODS: We treated 6-week-old anesthetized pigs with shock wave lithotripsy using an unmodified HM3 lithotriptor (Dornier Medical Systems, Marietta, Georgia) fitted with its standard brass ellipsoidal reflector (rigid reflector) or with a pressure release reflector insert. The pressure release reflector transposes the compressive and tensile phases of the lithotriptor shock pulse without otherwise altering the positive pressure or negative pressure components of the shock wave. Thus, with the pressure release reflector the amplitude of the incident shock wave is not changed but cavitation in the acoustic field is stifled. The lower pole of the right kidney was treated with 2,000 shocks at 24 kV. Glomerular filtration rate, renal plasma flow and tubular extraction of para-aminohippurate were measured in the 2 kidneys 1 hour before and 1 and 4 hours after shock wave lithotripsy, followed by the removal of each kidney for morphological analysis. In vitro studies assessed shock wave induced lysis to red blood cells in response to rigid or pressure release reflector shock pulses. RESULTS: Sham shock wave lithotripsy had no significant effect on kidney morphology, renal hemodynamics or para-aminohippurate extraction. Shock waves administered with the standard rigid reflector induced a characteristic morphological lesion and functional changes that included bilateral reduction in renal plasma flow, and unilateral reduction in the glomerular filtration rate and para-aminohippurate extraction. When the pressure release reflector was used, the morphological lesion was limited to hemorrhage of vasa recta vessels near the tips of renal papillae and the only change in kidney function was a decrease in the glomerular filtration rate at the 1 and 4-hour periods in shock wave treated kidneys. Red blood cell lysis in vitro was significantly lower with the pressure release reflector than with the rigid reflector. CONCLUSIONS: These data demonstrate that shock wave lithotripsy damage to the kidney is reduced when cavitation is suppressed. This finding supports the idea that cavitation has a prominent role in shock wave lithotripsy trauma.

Animals↗

PubMed2002

Urinary calculus containing gas.

The combination of gas in the upper urinary tract along with renal calculi has been reported in the setting of emphysematous renal infections, urinary tract instrumentation, and urinary-gastrointestinal fistulas. We present a case of a 46-year-old nondiabetic man with the isolated finding of a gas-containing renal calculus. The significant history in this case included recurrent urinary tract infections and primary hyperparathyroidism with persistent hypercalcemia despite previous parathyroid explorations. The patient was treated with oral antibiotics and rendered stone and infection free by percutaneous nephrolithotomy. The stone culture was negative, and the stone analysis revealed 100% hydroxyapatite.

Durapatite↗

PubMed2002

One versus two proficient laparoscopic surgeons for laparoscopic live donor nephrectomy.

OBJECTIVES: To compare the laparoscopic donor nephrectomy (LDN) results obtained by two different surgical teams, one consisting of a proficient laparoscopic surgeon assisted by an inexperienced laparoscopic surgeon and another consisting of two proficient laparoscopic surgeons. With more centers embarking on LDN programs, it is important to identify the factors that can improve overall outcomes during the initial learning curve. METHODS: A retrospective review was performed of the initial 70 sequential LDNs performed between October 1998 and March 2001 at our institutions. The procedures were stratified into two groups. Group 1 consisted of LDN cases performed by one proficient laparoscopic surgeon and an inexperienced laparoscopic surgeon (resident, fellow, or faculty) as the first assistant; group 2 consisted of cases performed by two proficient laparoscopic surgeons. RESULTS: Twenty-six LDNs were performed by group 1 and 44 by group 2. The total operative time and estimated blood loss showed a statistically significant decrease in group 2 compared with group 1, 143 +/- 32 minutes versus 218 +/- 38 minutes (P <0.001) and 92 +/- 115 mL versus 158 +/- 148 mL (P = 0.044), respectively. Two major complications occurred in group 1 (7.7%) and two major complications occurred in group 2 (4.5%). The 3-month postoperative recipient creatinine levels were similar for both groups, 1.6 +/- 1.3 versus 1.4 +/- 0.4 (P = 0.408). CONCLUSIONS: A surgical team composed of two proficient laparoscopic surgeons during the early learning curve of LDN may allow safe and efficient development of a laparoscopic live donor renal transplantation program.

Clinical Competence↗

PubMed2002

Laparoscopic treatment for ureteropelvic junction obstruction.

OBJECTIVES: To assess retrospectively the subjective and objective outcomes achieved after laparoscopic treatment for ureteropelvic junction obstruction at our institutions. METHODS: Between August 1999 and July 2001, 19 patients (11 women and 8 men), with a mean age of 31.2 years (range 17 to 67), underwent laparoscopic treatment for ureteropelvic junction obstruction. Of these, 17 patients were eligible for postoperative analysis. Nine of these patients had a history of prior surgical intervention on the affected side. The patients were subjectively assessed by an analog pain scale performed before and at least 6 months after surgery. Preoperatively, patients had a diuretic renal scan to confirm the presence of obstruction. Helical computed tomography was also performed preoperatively to assess for the presence of crossing vessels. The renal scan was repeated at least 12 weeks after surgery to document the relief of obstruction objectively. RESULTS: Helical computed tomography correctly predicted the presence of crossing vessels in 12 patients (63%). The Anderson-Hynes and Fenger pyeloplasty techniques were performed in 16 and 2 patients, respectively. In 1 patient, a small crossing vein over the ureteropelvic junction was identified and divided without complications. The average operative time was 240 minutes (range 128 to 470). The blood loss was minimal, and no open conversions were required. The mean hospital stay was 2.9 days (range 2 to 7). Two postoperative complications occurred (11.7%). The average subjective follow-up was 14.4 months (range 6 to 27), and the average objective follow-up was 7.8 months (range 3 to 12). Of 17 assessable patients, 16 (94%) had subjective and objective success (postoperative improvement in analog pain score and half-life of radiotracer washout). The average split renal function improved from 34.1% to 38.5% (P <0.01). CONCLUSIONS: On the basis of our data, laparoscopic pyeloplasty has a similar success rate compared with the traditional open approach and better results than other minimally invasive techniques. Longer follow-up and further experience are needed to validate these data.

Adolescent↗

PubMed2002

Percutaneous stone implantation in the pig kidney: a new animal model for lithotripsy research.

PURPOSE: This report describes a new animal model for research on the parameters of shockwave delivery and the mechanisms of shockwave action in SWL. MATERIALS AND METHODS: Female pigs (approximately 45 kg) were anesthetized for creation of an upper pole peripheral caliceal access. The tract was dilated with a 30F Nephromax balloon and Amplatz sheath, and a 24F rigid nephroscope was used to guide a gypsum artificial stone into a lower pole calix. An internal ureteral stent was then placed. After a 2-hour recovery period, lithotripsy was performed using an unmodified Dornier HM3 lithotripter. Following SWL, en bloc excision of the urinary tract was performed, and the stone fragments were collected. RESULTS: As observed by nephroscopy, most stones were surrounded by urine that was free of clot or debris. Urine output was >1 mL/kg per minute by the time the animal was positioned for SWL after a 2-hour observation period. When the conditions of shockwave (SW) exposure were 400 SWs, 20 kV, and 120 SW/min, the efficiency of stone fragment recovery was 85% +/- 2% (N = 6 stones). CONCLUSIONS: This procedure provides a minimally invasive method for placement of model stones of clinically relevant size within the pig kidney. Stone implantation is efficient and permits experiments to be conducted in 1 day. Stone fragmentation can be quantitated, and the animal can serve as its own control. Long-term experiments are also feasible. Overall, this new animal model is appropriate for experimentation on the parameters of SW delivery in SWL.

Animals↗

PubMed2002

Ureteroscopy as a first-line intervention for ureteral calculi in pregnancy.

BACKGROUND AND PURPOSE: Renal colic in pregnancy presents a diagnostic and therapeutic challenge. When conservative therapy fails or is not indicated, temporary measures such as ureteral stenting are often chosen as a first-line intervention, postponing definitive management until after delivery. We propose that advances in endoscopic equipment and anesthesia techniques dictate a more definitive strategy. PATIENTS AND METHODS: A retrospective analysis was performed on 10 consecutive pregnant patients presenting with renal colic necessitating intervention between April 1998 and April 2000. The mean patient age was 23 (range 17-31) years. One patient presented during the first trimester, six in the second, and three in the third. Four of the patients had a history of stone disease. All patients had flank pain at presentation, six on the left side and four on the right. Hematuria, fever, and nausea were present in eight, one and two patients, respectively. RESULTS: Ultrasound scanning was performed in all patients and showed a low sensitivity (28.5%) when compared with intraoperative findings. Ureteroscopy (rigid and/or flexible) was performed as a first-line intervention in six patients, in two of whom no stone was found. Percutaneous nephrolithotomy was carried out in one patient presenting with a nephrostomy tube. Double-J stents were placed in only three patients with specific indications, namely urinary infection, late gestational phase, and difficult ureteroscopy secondary to a narrow ureter. No obstetric or urologic complications were noted. The mean size of the stones retrieved in seven patients was 7 mm. CONCLUSIONS: Ureteroscopy may be considered a safe and effective first-line definitive therapeutic option in pregnant patients requiring intervention for stone disease.

Adolescent↗

PubMed2002

Transperitoneal laparoscopic renal surgery using blunt 12-mm trocar without fascial closure.

BACKGROUND AND PURPOSE: Conical blunt trocar insertion may eliminate the need for fascial closure (FC) in transperitoneal laparoscopic renal surgery. This concept applies to 12-mm blunt trocar placement through muscular parts of the abdominal wall, relying on muscle splitting and eventual muscle retraction when the trocar is removed. We retrospectively assessed the safety of fascial nonclosure (FNC) after 12-mm blunt port insertion. PATIENTS AND METHODS: Ninety transperitoneal laparoscopic renal procedures were performed between August 1999 and May 2000. Four ports (two 12 mm and two 5 mm) were usually used except for 30 donor nephrectomies, where an additional 5-mm port was used. The 12-mm trocars were inserted at the lateral border of the rectus muscle 5 cm below the costal margin and in the anterior axillary line 8 cm below the costal margin. Fascial closure was performed in 62 patients and nonclosure in 28 patients. Exclusion criteria for FNC included midline location, malnutrition, renal failure, and chronic use of steroids. Postoperative outcomes were compared in 20 patients with FNC matched with 20 patients with FC. RESULTS: At an average of 4.8 months of follow-up, none of the patients developed a trocar site hernia. No significant statistical differences were observed between the groups with regard to intraoperative and postoperative data. CONCLUSIONS: These two approaches appear to be equivalent in terms of patient morbidity and postoperative hospital stay. Fascial nonclosure after transperitoneal 12-mm blunt trocar insertion, through muscular parts of the abdominal wall may be safe and efficacious and eliminates the last step in transperitoneal laparoscopic renal surgery.

Adult↗

PubMed2002

Office-based transurethral microwave thermotherapy using the TherMatrx TMx-2000.

BACKGROUND AND PURPOSE: Transurethral microwave thermotherapy (TUMT) is an effective therapy for symptomatic benign prostatic hyperplasia (BPH), but the trade-off between the magnitude of clinical improvement and side effects and patient tolerance has limited its appeal to patients and urologists. This study, using the TherMatrx TMx-2000, a TUMT device that directly heats the transition zone to greater than 50 degrees C, has been focused on resolving these issues and developing a truly office-based therapy that is well tolerated with a benign post-treatment course. PATIENTS AND METHODS: This study was multi-institutional and designed as a blinded, randomized, and sham-controlled trial. A series of 200 patients with an AUA Symptom Index (AUASI) of >12, a peak flow rate of <12 mL/sec, and cystoscopic evidence of BPH were randomized 2:1 (active to sham) and treated in seven physician offices under a Food and Drug Administration-supervised and audited premarket approval protocol. No intravenous sedation was used in any patient. Follow-up for the sham-treatment group was 3 months, at which time, patients could cross over to an active treatment. A total of 119 patients have completed 1-year follow-up. RESULTS: The active and sham groups were statistically identical at baseline. The 1-hour total treatment was extremely well tolerated using urethral lidocaine and oral medications; not a single prostate block or parental dose of medication was required. The active-treatment group demonstrated a statistically significant reduction (p < 0.05) in AUASI at 3 months compared with sham treatment, with an AUASI decrease from 22.4 to 12.4 (n = 124) for active v 22.9 to 17 for sham (n = 62). For the 119 patients in the active arm who have reached 12 months, the AUASI has fallen to 10.6 points (47.1% decrease), and the peak flow rate has increased 5.0 mL/sec (58.1%). Postprocedure catheterization was typically 2 or 3 days, and the 16.8% of patients who failed their first voiding trial all voided within 1 week. No major adverse events such as stricture, rectal findings, or ejaculatory changes have been reported. CONCLUSIONS: This study demonstrates that the TherMatrx TMx-2000 TUMT effectively treats symptomatic BPH in the physician office with minimal morbidity.

Aged↗

PubMed2002

Endoloop-assisted laparoscopic partial nephrectomy.

PURPOSE: To determine the safety and feasibility of Endoloop-assisted laparoscopic partial nephrectomy in a large-animal model. MATERIALS AND METHODS: Twelve female Yucatan mini-pigs underwent either left (N = 6) or right (N = 6) transperitoneal laparoscopic lower-pole nephrectomy following cinching of a 1-0 Vicryl suture loop (Endoloop) proximal to the resected lower pole until ischemic discoloration was achieved. The ischemic lower pole was excised with Endo-scissors and the lower pole removed using a laparoscopic bag. Follow-up involved evaluation under anesthesia with retrograde pyelography and intravenous urography and subsequent sacrifice for pathologic evaluation at 3 (N = 4), 14 (N = 4), or 60 (N = 4) days. RESULTS: All procedures were completed successfully. In two cases, the Endoloop slipped off the retained parenchyma. Both problems were corrected immediately with no sequelae. At sacrifice, all upper-pole renal segments functioned, as shown by urography, and no urinomas or abscesses were found. In one animal, there was moderate hydronephrosis presumably secondary to ureteral scarring, and in another, mild extravasation was demonstrated on the retrograde pyelogram. CONCLUSION: We were able to perform laparoscopic partial nephrectomy with the Endoloop safely and effectively in the current model. Modification of the Endoloop to allow more controlled pressure application may allow clinical application of this method for polar laparoscopic partial nephrectomy.

Animals↗

PubMed2002

Topiramate-induced nephrolithiasis.

Topiramate is a recently developed antiepileptic medication that is becoming more widely prescribed because of its efficacy in treating refractory seizures. Urologists should be aware that this medication can cause metabolic acidosis in patients secondary to inhibition of carbonic anhydrase. In addition, a distal tubular acidification defect may result, thus impairing the normal compensatory drop in urine pH. These factors can lead to the development of calcium phosphate nephrolithiasis. We report the first two cases of topiramate-induced nephrolithiasis in the urologic literature.

Acids↗

PubMed2002

The effect of rate of shock wave delivery on the efficiency of lithotripsy.

PURPOSE OF REVIEW: The potential mechanisms of a shock wave rate effect are reviewed here, together with a report on the results of in-vitro, in-vivo and clinical studies that have assessed the effect of altering the shock wave rate on stone breakage and tissue injury by shock wave lithotripsy. RECENT FINDINGS: The vast majority of studies assessing shock wave rate have reported improved stone fragmentation and a reduction in shock wave lithotripsy-induced tissue damage with slower rates of shock wave delivery. However, the optimal shock wave rate has not been determined. SUMMARY: Slower rates of shock wave lithotripsy appear to improve the efficiency of this approach and therefore this suggests the need for a randomized clinical trial to assess shock wave rate.

Animals↗

PubMed2002

High resolution detection of internal structure of renal calculi by helical computerized tomography.

PURPOSE: There is considerable interest in using radiological imaging to predict kidney stone fragility before patient treatment. Case series of shock wave lithotripsy show that shock wave lithotripsy is repeated and/or ancillary procedures are done to remove shock wave resistant stones in a significant number of cases. If the fragility of stones were predicted at diagnosis, unnecessary shock wave treatment would be avoided. However, plain radiography allows little discrimination of stone type and simple numerical analysis of computerized tomography (CT) images by measuring Hounsfield units has been shown to be limited in its ability to predict stone fragility. MATERIALS AND METHODS: Urinary stones of known composition were imaged by helical CT in vitro at various slice widths and the images were assessed using a range of window settings. RESULTS: Visualization of stone structure was greatly enhanced using bone windows and a narrow slice width. Surface structure, such as crystalline leaves of calcium oxalate dihydrate, and internal structure showing the heterogeneity of composition or cracks were detected. Stones of similar mineral composition differed dramatically in terms of CT visible structure. CONCLUSIONS: Using a narrow slice width and bone windows greatly improves the visualization of kidney stone structure on helical CT. These results open up new possibilities for determining the relationship of stone structure and fragility for shock wave lithotripsy.

Humans↗

PubMed2002

Training postgraduate urologists in laparoscopic surgery: the current challenge.

PURPOSE: We established a new mini-fellowship training model for teaching laparoscopic urological surgery to practicing urologists that provides a learning experience beyond that of a pelvic trainer or hands-on, animal laboratory based laparoscopic course. It provides the practitioner with clinical experience under mentor direct guidance and supervision before embarking on independent laparoscopic surgery at an individual hospital. MATERIALS AND METHODS: A mini-fellowship model was developed that consists of 3 phases, namely 1) completing a 2 to 3-day hands-on course in laparoscopy, including pelvic trainers and an animal model, 2) observing a clinical mentor perform 6 or more major renal laparoscopic cases and 3) performing 6 or more major renal procedures under mentor direct guidance in trainee patients at the mentor or trainee hospital after obtaining appropriate temporary privileges. RESULTS: Two community urologists underwent the mini-fellowship program in 2000. Trainee 1 performed 30 laparoscopic procedures, including 17 radical nephrectomies, 4 simple nephrectomies, 4 nephroureterectomies, 4 renal cyst ablations and 1 renal biopsy, within the first 8 months after training and hospital accreditation. Trainee 2 performed 10 laparoscopic procedures within the first 3 months after training and hospital accreditation. CONCLUSIONS: This mini-fellowship model provides practicing urologists with a clinically applicable teaching experience to learn a new surgical concept using a familiar training pattern. It may be a more rapid and safe process of disseminating laparoscopic urological surgery to community urologists. Based on this model it would be possible for centers of excellence in each state to establish similar training programs for the corresponding urological community, thereby, bringing the teaching of new surgical skills to a more clinically relevant level.

Animals↗

PubMed2000

The effect of discharge voltage on renal injury and impairment caused by lithotripsy in the pig.

The present study was designed to determine the effects of shock wave voltage (kV) on lesion size and renal function induced by shock wave lithotripsy (SWL) in the 6- to 8-wk-old pig. Each SWL-treated pig received 2000 shock waves at 12, 18, or 24 kV to the lower pole calyx of one kidney. A group of sham SWL pigs served as time controls. Bilateral GFR, renal plasma flow (RPF), and para-aminohippurate (PAH) extraction were measured 1 h before and 1 and 4 h after SWL in all treated and sham animals. The kidneys were removed at the end of each experiment for morphometric analysis. The SWL-induced lesion increased significantly in size as shock wave energy was increased from 12 to 24 kV. PAH extraction, a measure of tubular function, was not significantly affected at 12 kV, was transiently reduced at 18 kV, and was reduced for the duration of the experiment at 24 kV. GFR and RPF, however, were significantly and similarly reduced at the 1 h post-SWL period at all three kilovolt levels. At the 4-h post-SWL period, both GFR and RPF had returned to baseline levels. Lesion size and tubular injury were correlated with changes in kilovoltage, while changes in renal hemodynamics were already maximal at the lowest discharge voltage. These findings suggest that renal microvessels are highly sensitive to shock waves and that frank injury to tubules and vessels may be more closely related to discharge energy than is renal blood flow.

Animals↗

PubMedDate not supplied

Shockwave lithotripsy: dose-related effects on renal structure, hemodynamics, and tubular function.

BACKGROUND AND PURPOSE: Shockwave lithotripsy (SWL) predictably damages renal tissue and transiently reduces function in both kidneys. This study characterized the effects on renal function of a supraclinical dose of shockwaves (SWs) (8000) in porcine kidneys and tested the hypothesis that such excessive treatment would intensify and prolong the resulting renal impairment. MATERIALS AND METHODS: Pigs aged 6 to 7 weeks were anesthetized and assigned to one of three groups. Groups 1 (N=8) and 2 (N=6) each received 8000 SWs at 24 kV (Dornier HM3) to the lower-pole calix of one kidney. Group 3 (7 pigs) received sham treatment. Renal function was monitored for the first 4 hours after SW treatment in Group 1 and for 24 hours in Group 2. Plasma renin activity was measured in Groups 2 and 3. RESULTS: The renal lesions produced by 8000 SWs comprised 13.8%+/-1.4% of the renal mass. In the 4-hour protocol, this injury was associated with marked reduction of the glomerular filtration rate (GFR), renal plasma flow (RPF), and urinary sodium excretion in both kidneys, although fractional sodium excretion was reduced only in the shocked kidneys. In the 24-hour protocol, GFR and RPF remained below baseline in shocked kidneys at 24 hours. Evidence of progressive ischemic injury was noted in shocked tissue at 24 hours after SW treatment. CONCLUSIONS: These findings support the hypothesis that the severity of the renal injury caused by SWL is related to the number of SWs administered and demonstrate the connection in this relation between renal structure and function.

Animals↗